1. Field of the Invention
The present invention relates to an X-ray generator and particularly to an X-ray generator in which a small-scale X-ray tube emitting soft X-ray is housed within a protective case. The present invention also relates to an electrostatic remover using the X-ray generator.
2. Description of the Prior Art
Japanese Patent Publication (Kokoku) No. HEI-7-50594 discloses one example of a conventional X-ray tube. In this X-ray tube, a filament heated by an electrical current flowing therethrough emits an electron beam, which is accelerated by a focus grid and the like and collides with the target at a high rate of speed. As a result, X-rays specific to the target materials are radiated outward from a translucent X-ray window provided in a spaced apart relation with the target. This type of X-ray tube reaches high temperatures and, therefore, must be cooled. A target ring which is fixed to the target and protrudes from the envelop (bulb) is provided for air cooling the X-ray tube, thereby maintaining the efficiency of the X-ray generation and preventing damage to the target. This type of X-ray tube is housed in a protective case including a power unit for generating a voltage of +9.5 kV and is incorporated inside the X-ray generator.
However, problems exist in conventional X-ray generators due to the configuration described above. In X-ray tubes of the type in which the target and translucent X-ray window are separated, the envelop is large, requiring a large space around the envelop to provide natural air-cooling. As a result, the protective case must also be large. Very small-type X-ray tubes in which the target and the translucent X-ray window (output window) are formed integrally were developed to solve the above problem. However, because of the very small size of this type of X-ray tube, the diameter of the envelop is also small, creating problems in achieving natural air-cooling and in incorporating the X-ray tube in existing protective cases.